Spiral corrugated pipe is widely used in the construction industry to make drainage conduits for water, sewage and other types of effluents. These systems may be located along or beneath highways, or for various other construction projects where diversion of water flow or drainage of runoff is required. Typically, the spiral corrugated pipe is manufactured of metal, plastic, or any other suitable material which has sufficient strength, durability and resistance to deterioration for a given application. Depending on the size and nature of the project, the dimensions of the corrugated pipe sections used to form the drainage system may vary. In order to construct the desired length of conduit, sections of spiral corrugated pipe are typically laid in end-to-end abutting relationships and then the adjacent ends are interconnected by pipe couplings to form a substantially fluid or soil tight seal at each joint of the constructed fluid conduit.
Couplings for joining sections of pipe must meet the same performance requirements as the individual sections of pipe. The connection must be soil-tight and it must not permit water to flow out at such a volume and velocity as to cause undue settling or erosion of the soil surrounding the pipe. If the pipe is to be situated below the water table, the pipe joints must also preclude the ingress of water. Furthermore, pipe joints must be sufficiently rigid to maintain the proper alignment of the joined pipe sections. Varying pressures on the ground above the joint pipe sections must not adversely affect the desired alignment. In addition to being able to withstand certain performance requirements, it would be advantageous to develop a coupling having an ease of use in the field.
Many different pipe coupling configurations are known in the art for interconnecting adjacent ends of pipe. For example, U.S. Pat. No. 3,501,179 issued to Boynton discloses a pipe coupling for adjoining adjacent re-corrugated ends of helical formed pipe. In this coupling, a flat band is tensioned about the adjacent ends of the pipe sections to form a continuous surface-to-surface seal about the entire circumference of the abutting pipe section ends. The surface-to-surface seal is provided by contact of the inner surface of the band and the outer surface of at least one of the annular corrugations formed on the re-corrugated pipe sections ends. A continuous surface-to-surface seal is provided about the entire circumference of each abutting end of the pipe sections when the ends of the bands are tensioned together. Resilient rings, such as soft rubber “O” rings, may be provided in the annular corrugations of the pipe sections to improve the surface-to-surface seal provided by the band.
U.S. Pat. No. 4,149,740 issued to Hall discloses a pipe coupling for joining adjacent ends of re-corrugated pipe sections. The pipe coupling includes a pair of semi-circular pipe sections that are mounted about the ends of the adjacent pipe sections. The semi-circular sections of the pipe coupling have annular corrugations that are adapted to engage with annular corrugations on the re-corrugated pipe section ends to securely couple the pipe lengths together.
U.S. Pat. No. 4,176,865 issued to Felton discloses a pipe coupling for providing a fluid tight seal between adjacent ends of re-corrugated pipe sections. The pipe coupling is formed as a pair of inner and outer flat bands that encircle the adjacent pipe section ends. The inner band provides a continuous surface-to-surface seal with the crests of the annular corrugations formed in the pipe section ends. The second or outer band overlies the inner band and is provided with cooperating loops and bolts for tensioning the outer band about the inner band to form a continuous surface-to-surface seal. The inner bands may be formed with annular corrugations to engage annular corrugations on the re-corrugated pipe section ends. Additionally, resilient rings may be provided within one of the annular corrugations on each of the re-corrugated pipe section ends.
While some prior art couplings have proved satisfactory for some applications of corrugated spiral pipe, one disadvantage of the current couplings is that they require the worker in the field to perform many difficult physical manipulations in order to effect the coupling of two adjacent sections of pipe. For example, regarding those cylindrical couplings which are already formed for application in the field, first the end of a section of pipe must be screwed into the coupling so that an annular ridge is positioned in an annular groove. Next, the coupling must be maintained at a fixed position while the adjacent section of pipe is swung in line with the coupling. Finally, at the same time as the pipe end is being swung in line with the coupling, the pipe end must be connected to the coupling. The difficulty involved in performing these manipulations increases with the diameter and weight of the pipes to be joined. Furthermore, the coupling of a plurality of pipes using such a coupling device is time consuming and requires excessive manpower.
Other prior art couplings require the cylindrical coupling to be formed in the field. This process requires a band to be rolled about and secured to two adjacent ends of pipe in the field. In order to accomplish this task, two adjacent ends of re-corrugated spiral pipe must be positioned and maintained in end-to-end relationship. Next, a flat band or sheet must be wrapped simultaneously around both pipe ends. The difficulty of this task is often increased by the need to match corrugations on the sheet with corrugations on the adjacent pipe ends. After the sheet has been wrapped around the pipe ends, it is tensioned in order to form a soil tight and/or water tight seal. Finally, the coupling is secured about the adjacent pipe ends by means such as welding or mechanical fasterners. This process is arduous and time consuming.
Thus, there exists a need for a coupling particularly adapted for joining adjacent ends of spiral re-corrugated pipe which is easy to install in the field without requiring extensive manipulation of the pipe ends. Moreover, there exists a need for a spiral corrugated pipe coupling which does not require complicated connections to form a connection at the pipe joint. Additionally, there is a need for a spiral corrugated pipe coupling which does not require simultaneously interconnecting two adjacent ends of pipe in the field.